1. Field of the Invention
The present invention relates to an apparatus for simultaneously unlocking a locked dead bolt functioning as an auxiliary locking device when a cylinder door lock's lever is turned on the inside, in order to promptly and conveniently open a door on the inside.
2. Description of the Related Art
Generally, both the cylinder door lock with a latch bolt and the dead bolt are both installed in a conventional door. This is because for security reason and the like the cylinder door lock alone is not completely sufficient for locking the door. Therefore, the dead bolt, which is superior to the door lock latch bolt in locking the door, is additionally installed so as to make the door move secure against external intrusion.
When opening the door from the interior side when the dead bolt is locked, it is required to unlock the dead bolt as well as turn the lever of the cylinder door lock. Such a dual motion causes a time delay that can be dangerous in the event of needing to promptly open the door, for instance when under a state of emergency like a fire.